The present invention relates to a swash-plate type rotary compressor such as a refrigerant compressor for use in an air conditioning system for vehicles.
In general, a swash-plate type rotary compressor is known in which a plurality of cylinders are disposed in circumferentially equi-distantly spaced relation to each other around a rotary shaft having mounted thereon a swash plate for rotation therewith and the swash plate is rotated to cause pistons to be slidingly reciprocated within the respective cylinders, to thereby compress gas or compression medium containing lubricating oil. In a compressor of this type, it is a requisite to lubricate balls and shoes through which the swash plate is engaged with the pistons, and to lubricate thrust bearings on the opposite sides of a central hub of the swash plate.
For this purpose, heretofore, as shown in FIG. 1, guide walls 2 and 3 are provided at an upper half portion of a swash plate chamber 1 and respectively on the opposite sides thereof. Gas or refrigerant drawn from a suction port 4 flows toward the swash plate chamber 1 through a low pressure passage 5 and an inlet bore 6a formed in a rear valve plate 6. The guide walls 2 and 3 serve to guide the gas to flow along opposite surfaces of the swash plate 1 from an outer periphery toward a center thereof. Subsequently, the gas is introduced into low pressure spaces 8 and 8 respectively through an outlet bore 7a formed in a front valve plate 7 and an outlet bore 6b formed in the rear valve 6. This enables the oil in the gas to be brought into contact with balls and shoes (not shown), and thrust bearings 10 and 11 on opposite sides of a central hub 9a of a swash plate 9, to thereby lubricate these components.
In such conventional compressor constructed as above, since the guide walls 2 and 3 are provided only at the upper half portion of the swash plate chamber 1 on the opposite sides thereof, a portion of the swash plate 9 located in the upper half portion of the swash plate chamber 1 is lubricated, but a portion of the swash plate 9 located in a lower half portion of the swash plate chamber 1 is not sufficiently lubricated. In addition, since the guide walls 2 and 3 are located remotely above the thrust bearings 10 and 11, only a small amount of gas flows to the central portion of the swash plate 9, and accordingly satisfactory oil lubrication is not effected of the balls and shoes, the thrust bearings, etc.